From: Bruce Boyes <bboyes@sy...> - 2009-01-18 00:40:08
A typical quartz crystal is +/- 50 ppm per deg C.
A typical SMT part (mfgr: PDI) is
Tolerance +/- 50 ppm at 25 C
Tolerance over temp: +/- 50 ppm per deg C but versions down to +/- 5
ppm per deg C are available.
Oper temp: -20 to +70 C
Aging: +/- 3 ppm per year
So 50 ppm is 50 x 10e-6 per deg C. Over 20 deg C that's 1 x 10e-3 or
0.1% if I did the math correctly.
I don't know the specific crystal used on Overo; this is typical data
for the crystals my company uses on similar systems.
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